FEDERAL SPECIFICATION NITROGEN, TECHNICAL

Transcription

1 NOTICE OF CANCELLATION [METRIC] NOTICE 1 June 1, 2000 FEDERAL SPECIFICATION NITROGEN, TECHNICAL Federal Specification, dated January 3, 1973, is hereby canceled and has been replaced by Commercial Item Description A-A MILITARY INTERESTS: CIVIL AGENCY COORDINATING ACTIVITY: GSA-FSS Custodians Preparing activity: Army - AV DLA-GS Navy - SH Air Force - 68 (Project ) Reviewers Army - AR, EA, MD Navy - AS, MC, OS, YD Other - DS AMSC N/A FSC 6830 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited.

2 January 3, 1973 SUPERSEDING FED. SPEC. BB-N-4116 September 10, 1964 FEDERAL SPECIFICATION NITROGEN, TECHNICAL This specification was approved by the Commissioner, Federal Supply Services, General Services Administration, for use of all Federal Agencies. 1. SCOPE AND CLASSIFICATION 1.1 Scope. This specification covers gaseous and liquid nitrogen. 1.2 Classification Types, grades, and classes. The nitrogen shall be of the following types, grades, and classes, as specified (see 6.2): Type I - Gaseous. Type II - Liquid. Grade A percent pure. Grade B percent pure. Grade C percent pure, moisture content not specified (type I only). Class 1 - Oil free. Class 2 - Oil tolerant (Type I only) (see 6.3). 2. APPLICABLE DOCUMENTS 2.1. Specifications and standards. The following specifications and standards of the issue in effect on date of invitation for bids or request for proposal, form a part of this specification to the extent specified herein: Federal Specification RR-C Cylinders, Compressed Gas: With Valve of Plug and Cap; ICC 3AA. Federal Standard FED. STD. No Marking for Domestic Shipment (Civilian Agencies). FSC 6830

3 (Activities outside the Federal Government may obtain copies of Federal Specifications, Standards, and Handbooks as outlined under General Information in the Index of Federal Specifications and Standards and at the prices indicated in the Index. The Index, which includes cumulative monthly supplements as issued, is for sale on a subscription basis by the Superintendent of Documents, U.S. Government Printing Office, Washington, DC ) (Single copies of this specification and other Federal Specifications required by activities outside the Federal government for bidding purposes are available without charge from Business Service Centers at the General Services Administration Regional Offices in Boston, New York, Washington, DC, Atlanta, Chicago, Kansas City, MO, Fort Worth, Denver, San Francisco, Los Angeles, and Seattle, WA.) (Federal Government activities may obtain copies of Federal Specifications, Standards, and Handbooks and the Index of Federal Specifications and Standards from established distribution points in their agencies.) Military Specifications. MIL-V-2 MIL-T Valve; Cylinder, Gas. - Treatment and Painting of Material Military Standards. MIL-STD-101 MIL-STD-105 MIL-STD-129 MIL-STD Color Code for Pipelines and for Compressed Gas Cylinders. - Sampling Procedures and Tables for Inspection by Attributes. - Marking for Shipment and Storage. - Palletized and containerized Unite Loads 40" x 48" Pallets, Skids, Runners, or Pallet-Type Base. (Copies of Military Specifications and Standards required by suppliers in connection with specific procurement functions should be obtained from the procuring activity or as directed by the contracting officer.) 2.2 Other publications. The following documents form a part of this specification to the extent specified herein. Unless otherwise indicated, the issue in effect on date of invitation for bids or request for proposal shall apply. DEPARTMENT OF TRANSPORTATION 49 CFR Code of Federal Regulations. (Application for copies should be addressed to the Superintendent of Documents, Government Printing Office, Washington, DC ) 2

4 NATIONAL BUREAU OF STANDARDS Handbook H28 - Screw-Thread Standards for Federal Services Application for copies should be addressed to the Superintendent of Documents, Government Printing Office, Washington, DC ) COMPRESSED GAS ASSOCIATION, INC. CGA Specification G-10.1 Commodity Specification for Nitrogen (first edition, dated 1969). CGA Pamphlet C-6 Standards for Visual Inspection of Compressed Gas Cylinders. CGA Pamphlet C-1 Methods for Hydrostatic Testing of Compressed Gas Cylinder. (Application for copies should be addressed to the Compressed Gas Association, Inc., 500 Fifth Avenue, New York, NY ) AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM). F Sampling Cryogenic Aerospace Fluids (Application for copies should be addressed to the American Society for Testing and Materials, 1916 Race Street, Philadelphia, PA ) 3. REQUIREMENTS 3.1 Materials. The nitrogen shall conform to table I. Table I. Properties of Nitrogen, Technical. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Property Requirement ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Grade A Grade B Grade C ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Purity, min. percent by volume Oxygen, max. percent by volume Moisture, max milgm HÚ2 O/1 of gas * Odor (see note 2) None None None ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ * No limiting characteristics 3

5 Notes: 1. Purity is the percent nitrogen and includes trace quantities of argon, neon, and helium. 2. All types and grades of nitrogen shall be free of oil contamination and shall have a total hydrocarbon level less than 50 ppm as methane by volume detectable by odor or by test when specified (see ). 3. Nitrogen, type I and type II shall be produced in processes utilizing liquefaction of air and compressed by a cryogenic liquid converter or a water sealed or dry sealed compressor. 4. The type I nitrogen shall contain no solid particles whose maximum dimensions are greater than 50 microns. This shall be assumed to have been assured by the use of a 10 micron or better nominal filter at or close to the cylinder charging manifold (see 6.4.). 3.2 Containers and valves Type I, gaseous. Unless otherwise specified herein, the type I gaseous nitrogen shall be contained in Government-furnished cylinders (see 6.5) which are in accordance with 49 CFR and equipped with valves having outlet connections in accordance with Handbook H28 or MIL-V-2 (see 6.3). When specified (see 6.2), new cylinders shall be furnished to the Government by the gas supplier. The cylinders shall be in accordance with RR-C-901 and shall be equipped with valves in accordance with MIL-V-2. When specified (see 6.2.), the gaseous nitrogen shall be contained in supplier owned, DOT approved containers Type II, liquid. Type II, liquid nitrogen shall be contained in either supplier owned or Government owned insulated containers or tank trucks as specified (see 6.2). Containers shall be in accordance with 49 CFR Container maintenance. Unless Otherwise specified (see 6.2), containers that require maintenance shall be precessed by the supplier for serviceability to meet the requirements of this specification and 49 CFR (see 6.6) Processing type I nitrogen cylinder External inspection. Each cylinder and valve shall be examined for external corrosion or damage in accordance with CGA Pamphlet C-6, and for clarity of markings in accordance with 49 CFR The area of the cylinder and valve shall be inspected for contamination. Cylinders having excessive corrosion, physical damage, evidence of exposure to fire or 4

6 evidence of a contaminate that cannot be removed by the supplier's standard handling procedures, or cylinders having a damaged or incorrect valve, or with unclear or incorrect marking shall not be refilled. When the contract or order does not provide for reconditioning of the Government-owned cylinder and valve, any defective cylinder shall be returned unfilled Hydrostatic testing. Each cylinder shall be inspected to determine the last date of hydrostatic testing. Unless otherwise specified herein, cylinders that have not been hydrostatically tested within 5 years prior to the intended fill date shall be hydrostatics tested and clearly marked in accordance with CGA Pamphlet C-1. Each cylinder subjected to the hydrostatic test shall be dried as specified in When the contract or order does not specify hydrostatic testing, any cylinder requiring hydrostatic test shall be returned to the Government unfilled. When specified (see 6.2), hydrostatic retest period shall be 10 years Cylinder drying. When required, all cylinders shall be dried by either the hot-gas purging method specified in , or by the evacuation method specified in Hot-gas purging method. The cylinder shall be dried by the cylinder valve, inserting a tube extending approximately to the closed end of the cylinder, and passing clean, hot (300 deg. to 350 deg. F.) dry oil free air or nitrogen through the tube until the temperature of the open end reaches 180 deg. F., or the escaping gas reaches 215 deg. to 225 deg. F. The cylinder shall be inverted with the open end down for this hot purge so that the longitudinal axis of the cylinder is not more than 45 degrees from vertical. The supplier's standard drying process shall be acceptable, provided it can be demonstrated that the drying process has eliminated the moisture from the treated cylinder determined by the dewpoint of the escaping gas becoming constant with that of the dry purging gas Evacuation method. The cylinder shall be dried by attaching a vacuum pump to the cylinder valve outlet, opening the valve, and heating the cylinder to approximately 180 deg. F. in an oven or hot water bath while evacuating the cylinder to a pressure of 3 inches of mercury (Hg) or better Residual pressure and odor. The cylinders shall be inspected for resident pressure and sniff-tested for odor. Any cylinder having no residual pressure shall be pressurized to not less than 25 psi of nitrogen pressure and checked for odor and any condensed contaminants. Any cylinder 5

7 having an odor or containing condensed contaminants which can not be removed by the supplier's standard handling procedure shall not be refilled. When the contract or order does not provide for reconditioning of the Government owned cylinders, the cylinders shall be returned unfilled Hammer test. During the inspection process, each cylinder shall be subjected to hammer testing for progressive corrosion or for the presence of contaminants which are not odor bearing. Cylinders that do not resound clearly shall not be refilled. When the contract or order does not provide for reconditioning of the Government-owed cylinders, the cylinders shall be returned unfilled Cylinder evacuation. Prior to filling, all cylinders shall be evacuated to a pressure of mercury (Hg) or better Painting. Government-furnished containers for nitrogen requiring repainting shall be cleaned, treated, and painted in accordance with MIL-T-704. The Government-furnished cylinders for type I gaseous nitrogen which are repainted shall be color coded and marked in accordance with MIL-STD Valves. Unless otherwise specified (see 6.2), replace valves for defective valves in Government-furnished cylinders for type I gaseous nitrogen shall be supplier furnished and installed and shall be in accordance with MIL-V Capacity. Containers of gaseous nitrogen shall be filled to the rated service pressure. The settled pressure in a filled container shall be within 25 pounds per square inch gage (psig) pressure of the pressure that corresponds to the settled container temperature as shown on Table II. Unless otherwise specified (see 6.2), containers of liquid nitrogen shall be filled to the rated capacity. Containers shall be filled in accordance with 49 CFR

8 TABLE II. Pressure-Temperature Conversion Chart. Settled pressure (expressed in psig) which corresponds to the rated service pressure for a container filled to capacity. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Settled Container service pressure--gaseous nitrogen Temp of ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ

9 TABLE II. Pressure-Temperature Conversion Chart. Settled pressure (expressed in psig) which corresponds to the rated service pressure for a container filled to capacity. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Settled Container service pressure--gaseous nitrogen Temp of ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ

10 TABLE II. Pressure-Temperature Conversion Chart. Settled pressure (expressed in psig) which correspond to the rated service pressure for a container filled to capacity. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Settled Container service pressure--gaseous nitrogen Temp of ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ 3.5 Leakage. Containers and valve shall not leak after being filled. 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility for inspection. Unless otherwise specified in the contract or purchase order, the supplier is responsible for the performance at all inspection requirements as specified herein. Except as otherwise specified in the contract or order, the supplier may use his own are any other facilities suitable for the performance of the inspection requirements specified herein, Unless disapproved by the Government. The Government reserves the right to perform any of the inspections set forth on the specification where such inspections are deemed necessary to assure supplies and services conform to prescribed requirements. 4.2 Classification of inspection. Inspection shall be classified as follows: (a) Quality conformance inspection (see 4.3). (b) Inspection of preparation for delivery (see 4.5). 9

11 4.3 Quality conformance inspection Inspection lot Type I, gaseous. A lot shall consist of all cylinders filled from the some source during a consecutive 24 hour period. A source is considered to be either an individual nitrogen producing process, or an individual storage container to which no nitrogen is added after the initial filling. Once nitrogen is added to a storage container from which cylinders are being filled, that storage container is prescribed as being a different source Sampling, Type 1. Sampling shall be from filled cylinders which shall be selected in accordance with MIL-STD-105, inspection level S Type II liquid. Each filled container shall be considered a lot Sampling, type II. Sampling of type II liquid oxygen shall be in accordance with ASTM F Standard Method of Sampling Cryogenic Aerospace Fluids Sampling, small containers. Type II nitrogen shall be drawn from each container. When specified (see 6.2), bulk liquid nitrogen used exclusively for filling an entire order of small liquid containers may be sampled and tested immediately prior to the actual transfer in lieu of testing samples from the small liquid containers Examination. Each container shall be examined as specified in Presence of one or more defects shall be cause for rejection Tests Individual. Each container shall be tested as specified in for leakage. Failure of the test shall be cause for rejection Samples. Samples selected in accordance with and shall be tested in accordance with AQL shall be 2.5 percent defective. The nitrogen sample for testing shall be representative of the type I nitrogen supplied in the cylinders. 4.4 Inspection procedure Examination. Each container of nitrogen shall be examined as specified herein for the following defects: 10

12 101. Container or valve not as specified Container maintenance not as specified Capacity not as specified Tests. Before any test, sufficient nitrogen shall be permitted to flow to displace any other gas present in the test equipment lines. Liquid nitrogen shall be in vapor form for the tests Purity and oxygen. The purity and the oxygen content, percentages by volume, shall be determined by Gas Chromatograph as outlined in or by one of the oxygen analysis methods specified in section 5.5 of CGA Specification G-10.1, with the following provisions: (a) The comparison tube apparatus described in of MA G-10.1 shall not be applicable. (b) Analytical instruments shall be appropriately calibrated and operated within the maximum range as specified in CGA G (c) Orsat apparatus, if used, shall be such that accuracy shall be at least plus or minus 0.01 percent by volume for grade A nitrogen and at least plus or minus 0.1 percent by volume for grades B or C nitrogen. (d) In case of dispute the gas, chromatograph method shall be the reference standard. Purity and oxygen content not as specified in 3.1 shall constitute failure of this test Gas chromatograph apparatus method. The purity of nitrogen shall be determined in accordance with the following gas chromatographic procedures: (a) Apparatus - A gas chromatograph having the following minimum capabilities is required: (1) Temperature control systems capable of maintaining the chromatographic column and detector at the prescribed temperature +/- 1 deg. C. (2) Gas sampling valve. (3) Not wire or thermistor type thermal conductivity detector. (4) Recorder or other readout. (b) Materials - The following materials are required: (1) Chromatographic column - A tubular column constructed of aluminum, copper or stainless steel, 6 feet long by 1/4 inch outside diameter. (Optimum column size will vary between instruments). The column is to be packed with activated Molecular Sieve 5A or 13X. 11

13 (2) Carrier Gas - dry helium of a minimum of volume percent purity. (3) Standards - Appropriate standards containing 0.05% by volume oxygen (Grade A) and 0.50% by volume oxygen (Grade B) may be obtained from Gas Supply Facilities or prepared in the laboratory. (c) Analysis Parameters - The following general analysis conditions are recommended. The parameters will between instruments. (1) Column temperature - 60 deg. C isothermal (2) Detector temperature (when separate from column) deg. C (3) Sample size - 0.5cc or as appropriate for instrument (4) Carrier gas flow - 20 ml per minute (will vary with instrument) (5) Detector current - sufficient to easily detect the oxygen requirement of Grade A or B. (d) Constituent identification - Employing the operating conditions specified, oxygen followed by nitrogen will elute from the column within 5 minutes. (e) Quantitative measurement - Quantitative measurement of a component concentration depends upon a determination of the peak height or peak area of the component's chromatograph peak. For the determination of oxygen, the peak is sufficiently sharp to recommend the use of peak height in lieu of peak area. To obtain the percent concentration of the oxygen component, a direct comparison is made between the peak height of the oxygen and that of a standard containing a known concentration of oxygen. Both the sample and the standard must be analyzed under identical operating conditions. The volume percent of the oxygen component may be calculated by using the following equation: % (Vol) OÚ2 - Peak Height OÚ2 in Sample X % (vol) OÚ2 in Std ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Peak Height OÚ2 in Std Moisture content. The moisture content shall be determined by either the accelerated gravimetric method as specified in or one of the moisture content analysis methods specified in section 5.3 of CGA G-10.1 with the following provisions: 12

14 (a) The condensed water measurement Method described in section of CGA C-10.1 is not applicable. (b) Analytical instruments shall be appropriately calibrated and operated within the maximum range as specified in CGA G Analytical apparatus shall be such that measurement can be made with a precision of at least plus or milligram water per liter of gas. (c) The 0.02 milligram water per liter of gas is equivalent to 26.3 parts per million water vapor by volume, and also to a dewpoint of minus 63.5 deg. F. Moisture content not as specified in 3.1 shall constitute failure of this test Accelerated gravimetric method. The moisture content shall be determined by measurement of increase in weight of phosphorus pentoxide (PÚ2 OÚ5 when subjected to a flow of a measured volume of nitrogen in the following procedure: (a) The container to be tested shall be inverted in a suitable rack. The container shall be connected to the test apparatus by means of a length of bent, seamless, corrosion-resisting steel tubing, and a high-pressure union needle valves and a glass-to-metal joint. (No rubber connections shall be used; a sleeve Joint secured with "tygon" or equivalent is acceptable). The apparatus shall consist of three U-tube absorbers-in series, each 4 inches high and 1/2 inch in diameter, containing phosphorous pentoxide on glass wool and connected through a water-saturator to a calibrated wet-test meter of 1/20-cubic-foot size equipped with a 1-liter dial. (b) A mercury safety valve shall be connected between the lower-pressure outlet of the needle valve and the first absorber. The steel tube shall be so fabricated that it will first pass through a water bath at room temperature and then into a second bath also at room temperature. The needle valve connecting cylinder to the absorber shall be flushed with nitrogen so that only gas discharged from the cylinder will pass through the absorber. The absorbers shall be brought to constant weight in a steam of dry nitrogen before they are weighed so they will be at all times filled with nitrogen. Before each weighing of the opened absorbers, they shall be opened momentarily to the air, closed, and cleaned. One-hundred liters of gaseous nitrogen shall be discharged through the apparatus at a rate not to exceed 0.4 liter per minute. 13

15 (c) The gas volume corresponding to the gain in weight shall be calculated to 760 mm. of mercury and 70 deg. F. The moisture content shall be computed in term of milligrams per liter Odor. Filled containers of nitrogen shall be sniff-tested. A sniff-test in made by wafting a low level of effluent vapor from a liquid nitrogen container or escaping gas from a nitrogen cylinder pot the tester's nostrils with a hand or a card. The detection of many odor in the effluent gas from any container shall constitute failure of this test Leakage. All containers after filling shall be tested for leakage by applying a soap solution to all portions of the valve and the junction of the valve and cylinder. Care shall be taken to ensure that the solution utilized does not contaminate the valve outlet. Any leakage as evidenced by bubbling of the soap solution shall constitute failure of this test Total hydrocarbon content. When specified (see 6.2), a total hydrocarbon content shall be determined by means of one of the total hydrocarbon methods specified in section 5.5 of CGA specification G Inspection of preparation for delivery. Each container of nitrogen shall be examined for compliance with the requirements of 5.1 and the marking shall be examined to determine whether any marking is missing, illegible, incorrect, or incomplete. Any one defect shall be cause for rejection. 5. PREPARATION FOR DELIVERY 5.1 Packing. Shipment of the containers of nitrogen shall conform to 49 CFR Palletization. When specified (see nitrogen contained in cylinders shall be pelletized in accordance with MIL-STD Marking. The containers shall be marking in accordance with 49 CFR Each container shall be stenciled or tagged with the type, grade, and class of nitrogen it contains Civil agencies. In addition to the marking specified in 5.2, the containers shall be marked in accordance with FED. STD. No Military agencies. In addition to the marking specified in 5.2, the containers shall be marked in accordance with MM-STD NOTES 6.1 Intended use. Gaseous nitrogen is used for pressurizing fuel tanks and hydraulic system accumulators, superpressurizing carbon dioxide and 14

16 fluorocarbon cylinders (e.g., fire extinguishers), purging equipment calibrating instruments, and providing insert atmospheres. Oxygen systems may be purged with class 1 nitrogen. The grade A nitrogen in a gaseous state is specifically intended for purging missile systems equipment. Grade A and grade B, class nitrogen are suitable for purging aircraft oxygen converters, pressurize aircraft struts, and purging and pressurizing rocket engine propellant systems. Liquid nitrogen is used as a cooling agent in low temperature processes, as an agent to shield against heat effects on temperature-critical apparatus, and as a source of gaseous nitrogen. 6.2 Ordering data. Purchasers should exercise any desired options offered herein, and procurement documents should specify the following: (a) Title, number, and date of this specification. (b) Type, grade and class of nitrogen required (see 1.2). (c) When new cylinders are to be furnished to the Government by the gas supplier or when the gaseous nitrogen is to be contained in supplier-owned containers (see 3.2.1). (d) Whether liquid nitrogen is to be delivery in supplier-owned or Government-furnished containers or tank trucks (see 3.2.2). (e) Extent of maintenance required on Government-furnished containers (see 3.3 and 6.6). (f) When hydrostatic testing is required every 10 years in lieu of 5 years, (see ). (g) When replacement valves for Government-furnished cylinders are not to be furnished by the supplier (see 3.3.3). (h) Quantity of liquid nitrogen required in a container, if loss than rated capacity (see 3.4). (i) When bulk liquid nitrogen way be tested in lieu of sample small liquid containers filled from bulk source (see ). (j) When total hydrocarbon content test is required (see ). (k) When cylinders are to be palletized (see 5.1.1). 6.3 Class 1 and class 2 nitrogen. Gaseous nitrogen is considered oil free, if the gas is compressed with a water-lubricated or dry-seal compressor or a cryogenic converter and if the gas is produced from a liquid nitrogen source. Liquid nitrogen is oil free by nature of the production process. Contamination would be caused by contact with contaminated equipment or by improper container handling methods. Cylinders for nitrogen are considered oil free if the cylinder meet the maintenance criteria specified in 3.3, or if the cylinders an internally cleaned to meet the oil-free criteria specified in RR-C-901. The container maintenance and nitrogen production requirements of BB-N-411 insure that both class 1 and class 2 nitrogen are handled identically. The only remaining difference between 15

17 classes is the valve-outlet application. Class I nitrogen cylinders utilize either connection 580 or 000, whereas class 2 nitrogen cylinders use connection 590. Connection 590 is obsolete for nitrogen service and is to be phased out of the Government system. Users should replace valves having connections 590 with valves having connection 580 in normal cylinder maintenance. The 000 connection is a non-standard outlet used to service artillery. Users should consider replacing the connection 000 with connection Particulate matter control. For some purposes, such as aircraft oxygen converter purging, pressurization of aircraft struts, and purging and pressurization of rocket engine propellant systems, it is important to control the nitrogen particulate matter content as specified in 3.1. Control of particulate matter in the user's dispensing equipment can be assured by the installation of a 10 micron or better nominal filter in the service line. 6.5 Government-furnished containers. The contracting officer should arrange to furnish the cylinders specified in Maintenance of Government-furnished containers. Purchasers should specify the extent to which Government-furnish containers that require maintenance should be processed by the gas supplier The gas supplier should furnish at no additional costs all services which are required at each and every filling of a container to comply with applicable regulations and normal practice. Such services would include, but not be limited to, all inspection, testing, evacuation, and handling services required for the gas supplied A schedule of allowable fees should be specified by the purchaser for the gas supplier's performance of services such as the replacement of valves, valve parts, and cylinder caps, hydrostatic testing, cleaning, painting, color coding, marking, and handling of unserviceable containers as required. All materials and components for these services should be furnished by the gas supplier. 6.7 Grade comparison. The limiting characteristics of the nitrogen grades specified herein are considered identical to those of grades presented in Compressed Gas Association (CGA) Specification for Nitrogen, G-10.1 as follows: GRADES ÄÄÄÄÄÄÄÄÄÄÄ BB-N-411 A B C G-10.1 (ed. 1969) G D C 16

18 BB-N Basis of purchase Type I (gaseous) nitrogen should be purchased by the cubic foot, based upon normal atmospheric conditions. Gaseous nitrogen is available in several cylinder sizes ranging from 180 through 340 cubic feet capacity at the rated service pressure Type II (liquid) nitrogen should be purchased by the pound or by the short ton. The following-conversion factors for liquid nitrogen should be used: ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Pound (mass) Liquid Liquid Cubic feet of gaseous Gallons Liters nitrogen at 70 deg. F. and 1 atmosphere pressure. ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ 6.9 International standardization. Certain provisions (see 3.1) of this specification are the subject of international standardization agreement ASCC Air Standard 14/6 and 14/10, and NATO STANAG'S 3443GGS 3546GGS and 3624GGS. When amendment, revision, or cancellation of this specification is proposed which will effect or violate the international agreement concerned, the preparing activity will take appropriate reconciliation action through international standardization channels including departmental standardization offices, if required. MILITARY INTEREST Custodians: CIVIL AGENCIES MD - GSA - AGR HEW - COM Army - ME Project No Navy - SH Air Force - 68 Review activities: Army - MD User activities: Army - GL Navy - YD, AS, NC Preparing activity: Army - ME ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Orders for this publication are to be placed with General Services Administration, acting as an agent for the Superintendent of Documents. See section 2 of this specification to obtain extra copies and other documents referenced herein. Price 20 cents each. 17